1,2,3,4-tetrachlorohexafluorobutane is an important compound as a raw material for synthesizing hexafluoro-1,3-butadiene that is notable as an etching gas used in fine processing for semiconductors.
As a process for producing 1,2,3,4-tetrachlorohexafluorobutane, there is, for example, a known process such that a compound represented by the formula CClX1X2—CClX3—CClX4—CClX5X6 (X1 to X6 are each independently a hydrogen atom or a fluorine atom) is allowed to react with fluorine in a liquid phase (referred to Patent document 1).
Patent document 1 discloses, as a solvent, perfluoroalkanes, perfluoroethers, perfluoropolyethers, chlorinated hydrocarbons and perfluoroalkylamines, and also discloses that it is especially preferred to use 1,2,3,4-tetrachlorohexafluorobutane as a solvent for fluorination reaction because there is no need of separation between the solvent and a reaction product. Patent document 1, however, still has an objective in the point of producing an aimed product in a high purity industrially, economically and efficiently because a reaction raw material is diluted with the solvent to carry out the fluorination reaction at low concentration.